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Finding the Fourth Proportional to 938.20, 1,292.20 and 813.86

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Solution

The fourth proportional to 938.20, 1,292.20 and 813.86 is: 1,120.94

Step by Step Solution

  1. Step 1: Write the proportion equation
    938.20 : 1,292.20 = 813.86 : x
  2. Step 2: Convert to fraction form
    938.20/1,292.20 = 813.86/x
  3. Step 3: Cross multiply
    938.20x = 1,292.20 × 813.86
  4. Step 4: Simplify right side
    938.20x = 1,051,669.89
  5. Step 5: Solve for x
    x = 1,051,669.89/938.20
  6. Step 6: Final answer
    x = 1,120.94

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1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.